Lazily initialize MessageLoop for faster thread startup

media/audio/audio_manager_base.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/audio/audio_manager_base.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 77 matching lines @@
   // CoreAudio calls must occur on the main thread of the process, which in our
   // case is sadly the browser UI thread.  Failure to execute calls on the right
   // thread leads to crashes and odd behavior.  See http://crbug.com/158170.
   // TODO(dalecurtis): We should require the message loop to be passed in.
   if (base::MessageLoopForUI::IsCurrent()) {
     task_runner_ = base::MessageLoopProxy::current();
     return;
   }
 #endif
 
+#if defined(OS_WIN)
+  // We check COM initializer status right after calling this, so wait here

[DaleCurtis, 2015/03/18 22:04:28]

Ah dang, I was hoping this one would be one we could remove since it's on the
BrowserMainLoop startup path.

[kinuko, 2015/03/19 03:08:16]

I haven't taken a deeper look but I guess we can probably fix this with some
refactoring in audio code, but so it'll need to be done in a separate bug/CL.

[kinuko, 2015/03/19 03:08:16]

I guess we can probably fix this but with some refactoring in audio code. We'll
need another bug/CL for this anyway.

+  // until we finish audio thread initialization (where we also run COM
+  // initializer).
+  CHECK(audio_thread_.StartAndWait());
+#else
   CHECK(audio_thread_.Start());
+#endif
   task_runner_ = audio_thread_.message_loop_proxy();
 }
 
 AudioManagerBase::~AudioManagerBase() {
   // The platform specific AudioManager implementation must have already
   // stopped the audio thread. Otherwise, we may destroy audio streams before
   // stopping the thread, resulting an unexpected behavior.
   // This way we make sure activities of the audio streams are all stopped
   // before we destroy them.
   CHECK(!audio_thread_.IsRunning());
@@ skipping 289 matching lines @@
 scoped_ptr<AudioLog> AudioManagerBase::CreateAudioLog(
     AudioLogFactory::AudioComponent component) {
   return audio_log_factory_->CreateAudioLog(component);
 }
 
 void AudioManagerBase::SetHasKeyboardMic() {
   NOTREACHED();
 }
 
 }  // namespace media